Olfactory ensheathing cell transplantation emerged some years ago as a promising therapeutical strategy to repair injured spinal cord. However, inhibitory molecules are present for long times in lesioned spinal cord inhibiting both OEC migration and axonal regrowth. Two of these families of molecules, chondroitin sulphate proteoglycans (CSPG) and myelinderived molecules (MAIs), are able to trigger redundant inhibitory responses in lesioned axons.
Here we analysed the inhibitory properties of MAIs o CSPGs in OEC migration. In addition, to avoid MAIs associated inhibition we generated a stable OEC cell line overexpressing the Nogo Receptor (NgR) ectodomain. Results indicate that engineered cells migrate longer distances than unmodified OECs over MAIs-coated substrates. In addition, cells expressing the NgR ectodomain also migrate longer distances in lesioned spinal cord.
Complementarily, we have utilized a microfluidic system with large open cell culture reservoirs to precisely control neuronal microenvironments, capable of mimicking axon transport and synapse formation and to facilitate their analysis. We demonstrate using this labon-a-chip system for long-term motoneuron co culture with C2C12-derived myotubes to mimic neuro-muscular junction (NMJ) formation. Furthermore, by integration with a calcium (Ca+2) imaging technique, we have proved the NMJ functionality in-chip through KCl-induced Ca+2 transient in connected myotubes. This platform can potentially become a useful tool as a straightforward, reproducible, and high-throughput in vitro model for basic NMJ research, and for high-throughput drug screening.